Improvement in bearing-blocks for bridge-trusses



. UNITED STATES PATENT OFFICE.

JOHN L. PIPER, OF ALTOONA, PENNSYLVANIA.

IMPROVEMENT IN BEARING-BLOCKS FOR BRIDGE-TRU SSES.

Specification forming part of Letters Patent No. 33,542, dated October22, 1861.

To all whom it may concern.-

Be it known that I, JOHN L. PIPER, of Altoona, Blair county, and Stateof Pennsylvania, have invented a new, useful, and Improved Bearing Blockfor the Braces of Bridges and Trusses; and I do hereby declare that thesame is described and represented in the following specification andaccompanying drawings.

The nature of my improved bearing-block for the braces of bridges andtrusses consists in making the tubes for the bolts or tierods separatefrom the bed of the block, so that they will yield or vibrate whenrequired without injuring or breaking either the bed or tube; also inrounding the ends of the tubes and fitting them to a curved seat in thebed, so that they will vibrate without materially lessening thebearing-surface between the bed and tube.

To enable others skilled in the art to make and use my improvedbearing-block, I will proceed to describe it, referring to theaccompanying drawings, in which the same letters indicate like parts ineach of the figures.

Figure 1 is a side, and Fig. 2 an end, elevation of myimprovedbearing-block. Fig. 3 is a plan of the under side with one of the tubesremoved.

In the drawings, A is the bed of the bearing-block, made of cast-iron inthe form shown in the drawings or in such other form as will answer thepurpose. The base B is designed to rest on the chords or string-pieces0. (Shown by dotted lines in Fig. 2.) There is a rib D in the center tofit a score cut across the chord O. The angles E E of the top of thebearing-block receive the ends of the braces F F. (Shown by dotted linesin Fig. 2.) This bearing-block is perforated at G G for the bolts ortie-rods of the truss, one of which rods is shown at H, Fig. 2, whichrod passes down through the tube I and is provided with a screw-nutwhich acts against the end of the tube and is not affected by theshrinking of the wood of the chord C. These tubes I I are made in theform shown or in such other form as will answer the purpose, andprovided with a hole for the bolts H. These tubes I I have flanges J Jprojecting from two sides and made in the form shown in the drawings,and

the upper end of the tube is rounded across the top, as shown by dottedlines in Fig. 1. This rounded end of the tube is fitted to a curved seator mortise K, Fig. 3. These tubes and also the bed A may be cast hollowby using cores in the molds to make them so. \Vhen the chords orstring-pieces of the bridge are fastened together,l out some places toreceive the tubes I I and drive them in, and then apply the bed on thetop of them and put the bolts or rods through and apply the braces, andthen screw up the nuts on the bolts. By making the tubes separate fromthe bed they can be fitted close and driven in tight with far less laborand made to fit much closer than if the tubes and bed were in one piece,for when the tubes and bed are in one piece it is very difficult to fitthem to the chords so that they will bear uniformly, and still morediflicult to screw up the bolts to the required pressure withoutbreaking the tubes or bed. Hence it often happens that the structure hasto be taken apart to remove a broken bearing-block and supply its placewith a whole one; but by my improved bearing-block, with tubes madeseparate from the bed, all the difficulty and inconvenience are avoidedand remedied, because the tubes yield or vibrate indepeudentot' the bed,and therefore neither of them is liable to be broken in screwing up thebolts or in applying them to the chords.

I believe I have described and represented my improved bearing-block forthe braces of bridges and trusses so as to enable any person skilled inthe art to make and use it.

I will now state what I desire to secure by Letters Patent, to wit:

1. Making the tubes for the bolts separate from the bed of the block, sothat they can yield or vibrate when required without injuring orbreaklng either the bed or table.

2. Rounding the ends of the tubes and fitting them to a curved seat inthe bed, so that they can vibrate without materially lessening thebearing-surface between the bed and tube, substantially as described.

JOHN L. PIPER.

Vitnesses:

J. DENNIS, Jr, J. F. CALLAN.

